Of course it's serious and not the first time that I've made it here. I have read articles that attempt to criticize this model for nutrition and fitness and I

Of course it's serious and not the first time that I've made it here. I have read articles that attempt to criticize this model for nutrition and fitness and I have rejected them. While the body may be a complex system, simple equations often effectively model complex systems. Think about predator/prey dynamics and the relatively simple differential equations that very effectively model it for biological research. The equation I stated is approximately how the body works and it is effective for all but the most aberrant scenarios. Of course there are limits - most people cannot lose or gain more than 2-3 pounds per week. Within those limits, this model is extremely effective. E and B are effectively independent. We're not trying to solve an equation here and get EXACTLY X amount of fat loss in Y amount of time. If you can estimate D to be approximately -500/day then you'll lose approximately a pound a week. You'll have more error in your measurement of B and E than you will see as a result of a change in metabolism. edit... fix typo and note that I currently weigh 187lbs and I used to weigh 225 lbs. This model was a very effective guide for me.